DEV: Add rswag to aid in api documention (#9546)

Adding in rswag will allow us to write spec files to document and test
our api.

spec/requests/api/categories_spec.rb

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+require 'swagger_helper'
+
+describe 'categories' do
+
+  let(:admin) { Fabricate(:admin) }
+
+  before do
+    Jobs.run_immediately!
+    sign_in(admin)
+  end
+
+  path '/categories.json' do
+
+    post 'Creates a category' do
+      before do
+        Jobs.run_immediately!
+        sign_in(admin)
+      end
+      tags 'Category'
+      consumes 'application/json'
+      parameter name: :category, in: :body, schema: {
+        type: :object,
+        properties: {
+          name: { type: :string },
+          color: { type: :string },
+          text_color: { type: :string },
+        },
+        required: [ 'name', 'color', 'text_color' ]
+      }
+
+      produces 'application/json'
+      response '200', 'category created' do
+        schema type: :object, properties: {
+            category: {
+              type: :object,
+              properties: {
+                id: { type: :integer },
+                name: { type: :string },
+                color: { type: :string },
+              },
+              required: ["id"]
+            }
+          }, required: ["category"]
+
+        let(:category) { { name: 'todo', color: 'f94cb0', text_color: '412763' } }
+        run_test!
+      end
+    end
+
+    get 'Retreives a list of categories' do
+      tags 'Category'
+      produces 'application/json'
+
+      response '200', 'categories response' do
+        schema type: :object, properties: {
+          category_list: {
+            type: :object,
+            properties: {
+              can_create_category: { type: :boolean },
+              can_create_topic: { type: :boolean },
+              draft: { type: :string, nullable: true },
+              draft_key: { type: :string },
+              draft_sequence: { type: :integer },
+              categories: { type: :array },
+            }, required: ["categories"]
+          }
+        }, required: ["category_list"]
+        run_test!
+      end
+    end
+  end
+end